Bp or K8??

[DeadMaker]

Hello.I have found two donor cars form swapping my 1.6 doch engine.
First car is mx3 92 v6 and second 323 92 bp.
The price is the same.The condition of these engines seems good..After the swap i will stay in these hp as i am not planning to increase it(At least in the near future).
So which is the best idea for you guys?Which engine i should choose?
Thx

[kulluminati777]

If your staying the same then go with the K8

If you may be increasing power and going turbo than go BP

[RobMinhas]

BP will be a much easier install and you'll be able to use your factory shift linkage and a couple of mounts as well as your trans. For the k8 you'll need to use all of that from the donor car which will be a bit more work. The k8 mx3 will have rear discount brakes though so you can swap all of that in too.

[DeadMaker]

What about the engine power?I know the numbers are pretty much the same but which motor will give more nerve?

[Evo_Spec]

K8 will be slightly higher hp but at the cost of taking up pretty much every bit of the engine bay space so working on them inside the car is next to impossible, for that reason alone i'd go with BP, especially because it's so easy to boost.

[DeadMaker]

Having the full harness and ecu of the bp will i need to cut and split any wire?or is only plug and play in ALL situation?

[RobMinhas]

For the BP, what you 'll need to do the donor car is:

1. Unplug the wires from the back of the ECU, which is located right behind the center console, behind your stereo. You will have to remove the trim on either side to get to the bolts that hold it down.

2. Follow the plugs you unplugged from the back of the ecu, they might be taped around other wires so you might have to cut them out of that, more then likely it will be by itself.

3. Look behind the intake manifold in the engine bay, on the firewall there is a circular "plug" with wires going through it, pull that plug towards the engine, then pull out the plugs for the engine harness through that hole.

4. Follow that wire loom(bunch of wires taped together) it will go around the top of the firewall towards the battery, you'll have to get it off of that.

5. Simply unplug all of the plugs from the harness, I recommend that you label them with tape and a marker. There will be a few that are bolted down grounds, simply undo those.

THen when you put the BP in it's the opposite of that.


However your MX-3 is OBD2 since it's a 1997. This may complicate things so I'd recommend you search around to see if anyone else has done this first, what I told you will work to get teh harness out and in but I don't know if that changes other things about the car.

[DeadMaker]

Will i need to change the cluster too for the bp swap?
Cause mine is digital and as far as i know 92-93 soch where cable..

[RobMinhas]

Yeah you'll need a cluster from a 92-93 RS but the donor car should have the speedo cable already.

[Surgeonasst222]

If u think u are going to boost and turbo the car go bp, but if u really never know if u are going to do it or not...

I would do a k8, u are making the engine fit either way and if u have the time... But I am not like all the other people on here that want to force u into turbo

IMO doing the k8 puts u in KL territory, these engines put out the power and let u keep your a/c... Cool air is nice when it is hot

As someone said on these forums:

Remember we drive sport cars, not race cars

The k8 might suck for space reasons and such but more power doesn't come at the cost of expensive turbo set ups and losing normal everyday items like a/c, when u want more power with your v6 when ready u just put KLDE or KLZE... again IMO

but again this is all in how much work u want to do

[DeadMaker]

I think you can obtain the ac system and fit a turbo with a little space work..K8 unfortunately needs too much work and in the end you have the same power as the bp..

[DeadMaker]

Yeah you'll need a cluster from a 92-93 RS but the donor car should have the speedo cable already.

But the donor car must have a speedo sensor and electric cable if it has g series transmission..So it must fit with the 94+cluster.
Isn't that right?
F25mr are made with speedo sensors and not mechanical cable..
I am little lost..

[RobMinhas]

I was assuming that the BP came with either an f series or g series that is mechanical, however it could have a g series that is electric(from a GS MX3) or an f series that is electric(I believe this to be true, however i don't know if a BP will pair up with an f series trans).

The F25mr came with both electric and mechanical/cable. The 92-93 RS came with the manual/mechanical/cable and the 94+ came with electric. All of the RS's came with F series transmissions.

If the donor car has a g series transmission from a MX-3 GS(or perhaps another car, I know you are overseas so it may be in some other mazda, in North America that's the only way to get an electric G series, that I know of) it will be electric and will work with your cluster.

I really doubt it is though because I believe you need to modify the electric G series transmission to get it to pair up with the BP so it's more likely either a manual speedo G series or F series.

If any of this is confusing let me know and I'll try to clarify. If you need answers ASAP you can PM me and it'll go straight to my phone so I can reply quick.

[Josh]

OK.

The B6 and BP motors share the same bell housings. All BP motors use a G series trans. This trans is a different bell housing than an MX3 GS G series trans.

All B6 motors came with a F series trans. Now they will interchange as in F series will fit a BP and a G series will fit a B6 but you will have to also change the flywheels accordingly as well.

Your 94-95 F series trans uses an electric speedo, you do not have to convert to a manual speedo, I never did. All you have to do is make a 1/2" shim or spacer to go between the gear and the mounting point. The only relation the BP G-series trans has with the GS model is the internals. the casing is different.

I made a shim using a dremel and a 1/2" thick piece of plexy glass. I ran it for several years with no issues. I just used a longer bolt to bolt it down and rtv to seal it up. I think I ended up selling it to someone when I did the AWD swap. It took me all of about maybe 30 minutes to make.

Another option would be to do what I did on my AWD trans. I used the lower section of the Manual cable drive then pulled the gear off of the Electric speedo, notched the end so it would go into the end of the manual speedo and then used a nice thick piece of fuel line and hose clamps to couple and hold them together. Jimmy rigged, yes, but it works with no issues.

[DeadMaker]

So in a few words there is no reason to change my cluster while i will be using bp with g series trans.
Thanks..